Synthesis of side-chain liquid crystalline polyurethanes via ester type attachment

Summary

A series of side-chain liquid crystalline polyurethanes was prepared by reacting a COOH functionalized polyurethane with monomers based on a biphenyl core with a methoxy terminal group and spacers of different lengths (α-bromo-ω-(4'-methoxybiphenyl-4-oxy)alkanes) in the presence of triethylamine. FTIR and NMR spectroscopic analysis of the products revealed that the monomers were attached to the polymer backbone as side chains by covalent, ester bonds. Thermotropic liquid crystalline behaviour of the ester type derivatives was analysed by differential scanning calorimetry and polarizing optical microscopy. All products exhibited smectic mesophases of highly ordered focal-conic structures.